Conventionally, such prostheses are selected by the surgeon from a set or kit of standard sizes and shapes of plates or strips having pre-drilled holes for screws. These may be capable of some limited bending and/or cropping to adapt a specific size of strip or shape to more closely suit the circumferences of any particular fracture. Generally speaking, however, the type of pinning possible using these conventional prostheses is limited in scope because of their 2-dimensional configuration which is often unsatisfactory from both a surgical and mechanical strength point of view.
The difficulties involved in bending have led to proposals for mechanical aids to bending so-called osteosynthetic plates during surgery, such proposals being contained in DE-OS-37 24 479 and DE-OS-29 20 223. However, these aids do not facilitate anything like the full range of prosthetic shapes necessary and even so require still a considerable inventory of shapes and sizes of osteosynthetic plates.
A wider range of prosthetic shapes would facilitate different and better pinning techniques, but the prefabrication of a complete range would be a near-impossible task and the maintenance of a comprehensive inventory to cover all eventualities prohibitively expensive, to say nothing of the difficulty of selecting a shape and size from such a plethora of possibilities.
The custom-production of prostheses precisely adapted to a particular fracture has to date been substantially ruled out because of the time required to produce such prostheses by conventional production techniques and the lack, in any event, of workshop facilities close to the operating theater.